Recoilless firearm and ammunition therefor



May 13, 1958 c w. MUSSER '2,334,255

REcoILLEss FIREARM AND AMMUNITION THEREFOR Filed Aug. 27, 1952ATTORNEYS1 RECOILLESS FIREARM AND AIVIMUNITION TIEREFOR C Walton Musser,Philadelphia, Pa., assigner to the United States of America asrepresented by the Secretary of the Army Application August 27, 1952,Serial No. 306,743

1 Claim. (Cl. 89--1.7)

(Granted under Title 35, U. S. Code (1952), sec. 265) The inventiondescribed herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment of any royalty thereon.

yMy invention relates to recoilless firearms `(i. e., rearms in whichthe recoil forces incident to tiring are neutralized by substantiallysimultaneously occurring counterforces derived from gas pressures `alsoincident to firing) and to ammunition especially associated andcofunctioning therewith.

In speaking of recoil forces incident to firing, I make reference to therearwardly acting recoil forces, of such strength as to warrantcounteraction, exerting their inuence, largely, along the axis of therearms barrel and causing the barrel to kick back (i. e., move in adirection opposite that taken by the projectile); and I make reference,also, to the rotationally acting recoil forces, of such strength as towarrant ccunteraction, exerting their influence, largely, as a torque onthe firearms barrel and tending to cause the barrel to rotate about itsaxis in a direction opposite that of the spinning projectile.

Those skilled in the art knowithat yrearwardly acting recoil forces ofsuflicient magnitude to lwarrant counteraction are found in both smoothand ried bore iirearms of large caliber, and that the rotationallyacting recoil forces of sufficient magnitude to `warrant counteractionare found in rifled bore firearms of large caliber.

Therefore, with reference to smooth bore firearms, my invention pertainsto the neutralization of the rearwardly acting recoil forces incident tofiring by means of a forwardly acting counterforce derived from the gaspressures also incident to firing and occurring .substantiallysimultaneously therewith; and, with reference to ried bore firearms, myinvention pertains to the neutralization of both the rearwardly actingand the rotationally acting recoil forces incident to vfiring by meansof forwardly acting and contra-rotationally acting counterforces,respectively, derived from gas pressures also incident to firing 'andoccurring `substantially simultaneously therewith.

An inspection of the prior art will disclose many various ways whichhave been devised to neutralize undesirable recoil forces. Thatinformation is well known to those skilled in the art and, therefore,need not be discussed at length here. Although many of the meansheretofore provided have been more or less successful, no one has soughtto neutralize recoil forces in the manner I am about to disclose.Therefore, the many later to be mentioned benefits and advantagesattending the manufacture and use of my invention previously haveneither been known nor enjoyed.

Essentially, my novel recoilless firearm is distinguishable fromanalogous prior art devices by my combination of an ammunition roundhaving an imperforate cartridge case, a plurality of openings in the gunbarrels wall, and an axially extending, annular venturi passagesurrounding the rear portion of the rearms barrel. The ammunition roundis distinguishable from prior art ammunition rounds A2,334,255 PatentedMay 13, 1958 by the means I have provided for securing the ammunitionround in the firearm.

In practicing -my invention, I provide a gun tube having a slender,relatively thin-walled, forward barrel portion which blends into asomewhat larger diametered, relatively thicker-walled, concentric rearchamber portion. This chamber portion is adapted to accommodate thecartridge case of the ammunition round, while the barrel portionaccommodates the rounds projectile.

Secured -coaxially to the barrels rear portion, just ahead of itsconiuence with the chambers forward portion, is a recoilneutralizing'sleeve. This sleeve is provided, interiorly, with anaxially extending conical opening which tapers outwardly from front torear. At the forward or smaller end of this opening there also isaxially extending a concentric, but somewhat larger diametered recessconveniently shaped for maximum operating eiiiciency.

It will be noted that the interior surface of the sleeves conicalopening and the recess adjacent the openings smaller end, in conjunctionwith the exterior surfaces of the chamber and barrel, form an axiallyextending, annular venturi passage completely surrounding the chamber.The smaller diametered end of the sleeves conical opening substantiallyradially opposes the junction of the barrel and chamber to form theventuris throat, or constricted portion. The sleeves shaped recessadjacent the conical openings smaller diametered end and part of thebarrel form the input portion of the venturi (i. e., in front of thethroat); and the sleeves conical opening and the outer surface of thechamber form the output portion of the venturi (i. e., to the rear ofthe throat). Because of the way in which the recoil neutralizing sleeveand the barrel are joined, the venturis input portion is closed to theatmosphere, but its output portion is open to the atmosphere.

Eiecting communication between the barrels bore and the forward, inputportion of the venturi are a plurality of openings. These openings arelocated in the Wall of the barrel immediately in front of its junctionwith the chamber. With the ammunition round in place within the chamber,these openings are commencing substantially on a line `with or justslightly forward of the cartridge cases neck end so that all gasesissuing from the case upon ignition of the powder therein `will `exittherethrough and rearwardly substantially simultaneously 4with theforward movement of the projectile.

Although it is possible, by the addition of a breech block, to adapt thebarrel of my recoilless firearm to accommodate ammunition rounds havingimperforate cartridge cases of conventional design, I find that themerits of my recoilless firearm can be further enhanced by the usetherewith of the ammunition round l have'especially provided.

In this novel ammunition round, the cartridge case is provided with aplurality of radially projecting lugs which are intended to engage acorresponding number of :similarly shaped and spaced lugs located insidethe firearms barrel. The ammunition round is secured in the barrel byinserting the round, then turning it so that the ycartridge cases lugsand the barrels lugs interlock to prevent the Acartridge cases rearwardaxial displacement relative tothe gun when the round is fired. Afterfiring, the cartridge case remaining in the barrel is removed byreversing the process.

Relative to a smooth bore firearm, when the ammunition round is firedthe force generated by the exploded propellent, in addition to ejectingthe projectile, causes a rearwardly acting recoil force tending todisplace' the barrel in a rearward direction. However, with my invenfmunition roundris fired, the force generated by theexploded'fpropellent," inaddition to ejecting. the projectile,

causesfa rearwardly acting recoil force as before, and

theprojectile in'traversing the lengthrof the ried bore induces arotationally'acting recoil force. Both recoil forces; however; areeifectively neutralized throughthe operation'of'my invention. Y

Because ofthe' ininitesimally small time interval between `theA actionAof the recoil force, or forces, as the casemay be, andthe action of therecoil neutralizingv counterforce or'V counterforces, respectively,those two actions can be considered as action and reaction,respectively; occurring simultaneously in direct opposition. By properlybalancing, the existing recoil (or action) and the requiredcounteraction (or reaction), the'netresult is zero recoil in eitherdirection.

One object of my invention is to simplify the design, construction, andoperation of recoil-free guns.

Another object is to provide a recoilless rie using an imperforatecartridge case.

Afurther object is to provide a recoilless rifle wherein more eicientburning of the ammunition rounds propellent powder is accomplished.

A still further object is to provide a recoilless rifle in which theamount and temperature of the rearwardfow of 'gases used to neutralizerecoil-l are reduced.

, Fig; 1' gun. showing further4 details of my invention; and

An additional object is to provide a recoilless rifle in which theprojectile, after being red, acts as a valve influencing the action ofthe propellent powders gases on the venturi.

Theforegoing and other objects and advantages of Fig. 3'is'a crosssection taken along Vline Y3 3 offFig, 1 showingother4 details of thepresentinvention.

, the barrels wall.

. 41 l 17"tliat^terminates at'a flange 18l which is also locatedton thebarrel. This ange, it will be shown later, serves asa seat for recoilneutralizing sleeve 11 when that sleeve is joined to thefbarrel.

Formed in the wall of the barrels rearmost portion, between itsconfluence with chamber 13 and ange 18, are a plurality of openings 19(see Figs. 1 to 3). These openings, which may be of any convenient sizeand shape, depending upon various parameters, ,prefrablyfare spaced atequal angular intervals relative to the barrels axis and aredimensionedto .present a. certaintotalarea` of opening.

Fig. 3 shows openings 19'as extending radiallythrough This has been donebecause, in the illustrated embodiment, only a rearwardly actingirecoilforce is of such magnitude as to require counteraction. As earliermentioned, my invention also contemplates the neutralization of arotationally acting recoilforceg: ifit should be'of such magnitude as towarrant counteraction, as is Vthe case with rifled guns. In thelattercase, openings 19, instead of b eingformed on imaginary radiallines, as.v indicated inFig. 3, would be formed on imaginary chordal.lines (not shownywhose direction would beV opposedjto thatv ofthe riingsin the gun barrel, so as to enable the gases flowingtherethrough toinduce a torsional force on barrel 10 to neutralize rotational recoil.

Internally, chamber 13 is provided with the convenient-` ly shaped anddimensioned ammunition recess 21.wh'icl1 matingly accommodates cartridgecase of ammunition roundi12. Issuing from Vthe forward end of theammuni.y tion recess and extending through the barrelsforward portion 14to the muzzle (not shown) is the bore 22 (seeA Fig. 2). This bore isrepresented ashaving riing com-v prising the lands 24- and the grooves25. However whether or not the bore is rifled is of no critical im,portance to my invention. The ried boreis shown only because theprojectile 26 forming part of ammunition.

. round`12 is provided with a rotating band 27 Whichopf- The basicYstructural components of the illustrative I embodiment of` my inventionare the barrel 10, the

chamber 13, the recoil neutralizing sleeve 11, andV the'r ammunitionroundA 12. The essential details of these components will now bedescribed.

Barrel and chamber from ignition of the ammunition rounds propellent.Actually, however, it is possible to make the chamberl and barrel in twoseparate Vparts, skillfully designingV their juncture so as toaccomplish the same ready gas flow.

Infthe illustrated embodiment, chamber 13, for practical reasons, is.represented as having atapering diameter which increases from itsforward end 15 to` its; rear end 16.. However, it isnot to be construedthat this condition,

althoughpreferable, is mandatory. Actually, chamber 13r co uld,.y ifdesired, be of cylindrical or-other'geometric shape.

The, rearmost portion. of barrel 10 is.provided,' nea l its confluencewith chamber 13, with an external thread tionally may be pre-engraved,as shown, or plain (not shown).

rotating band, bore 22 normally would bey smooth.

Formed in the rear end of ammunition recess 21, and;

concentric therewith, is a somewhat larger diametered re= 'Y cessvhavinga thread,30 whose root diameter (i. e., the diameter near Vtheammunitionrecesss axis) is somewhat'l larger than Vthe ammunition 'rounds recess.As will later be shown, this thread forms a convenient means for secur.-e ingcartridgecase 45 of the ammunition round incharnber. 13. In order.to facilitate and to hasten thisprocessras:v well as. the removal of acartridge case remainingi'infthef barrel afterring, thread 30 maybeinterrupted byja plu? rality ofaxially extending paths, preferablyVequally spacedY and of equal angular expanse relative tothe lbarrelsaxis.

Recoil neutralizing sleeve Recoil neutralizingv sleeve 11, as showninFigs. 1 ax1d2,. comprises a rear portion 33' and a forward, neckpor.-tion'34. Y

Rear portion 33 is provided with a conical openingmb whosef smallerdiametered end36 is toward the barrels openings 19,- and whoselargerdiametered end'37"is to, wardthechambers rear end 16. Y

Forward VneckY portion 34V is provided- With a recess- A38'whichis-adjacent to, but somewhat lar-gerin diameter; than,.theconicalopenings' smaller end`36.-` Asbest shown' Shouldtheprojectile not be equipped with a in Figs. 1 and 2, recess 33 has aparticular shape relative to conical opening 35.' As with the blendingbetween chamber 13 and barrel 1G, the shape of recess 38 is for thepurpose of permitting optimum operation of gases produced yby ignitionof the ammunitions propellent. Adjacent this recess, and also in therecoil neutralizing sleeves forward portion 34, is the threaded opening39 by means of which the recoil neutralizing sleeve is later assembledto gun barrel 1G.

On the exterior of the recoil neutralizing sleeve is the electricalterminal block 4f) having the quick connect-disconnect contact 41 (seeFig. 1). This contact is connected by the electricity-conducting wire 42to one side of a convenient source of electricity (not shown). The otherside of the source of electricity is connected to barrel by means of theelectricity-conducting wire 43 (see Fig. 1).

The recoil neutralizing sleeve is assembled to barrel 10 by passing thebarrels forward portion 14 through the sleeves forward, neck portion 34,and then engaging the sleeves thread 39 with the barrels thread 17 untilthe inside of the neck portion is sealingly seated against the barrelsflange 18 (see Figs. l and 2). The barrel therefore, completely closesthe forward end of the sleeves neck portion 34.

When properly assembled, the sleeves recess 38 lies spacedly opposed tothe barrels openings 19; the smaller diametered, forward end 36 of thesleeves conical opening is toward the barrels flange 18, and thatopenings larger diametered, rear end 37 is toward the chambers rear end(see Fig. l). In addition, the interior surface of conical opening 35and adjacent recess 38, in conjunction with the concentric externalsurface of barrel 10, define an uninterrupted annular venturi passagesurrounding the chamber (see Figs. l to 3). As shown in those figures,smaller diametered end 36 of the sleeves conical opening 35substantially opposes the confluence of barrel 10 and charnber 13 toform the venturis throat (i. e., the constricted portion); the sleevesrecess 3S adjacent the conical openings smaller diametered end 36 andpart of the barrel which contains openings 19 form the forward or inputportion of the venturi (i. e., in front of the throat); and the sleevesconical opening 35 and the chamber form the output portion of theventuri (i. e., to the rear of the throat).

Ammunition round Ammunition round 12, for the most part, resembles wellknown ammunition rounds in that it comprises a cartridge case 45, aprimer 46, earlier-mentioned projectile 26, and propellent powder 47.

Primer 46, preferably electrically detonatable through the agency of theelectricity-conducting wire 48, connected to a heating or spark element(not shown) within the primer, is accommodated in usual fashion in thehead end 49 of the cartridge case.

Earlier-mentioned projectile 26 is accommodated in any convenient mannerin the neck end 50 of the cartridge case and, optionally, is providedwith the aforementioned rotating band 27. As mentioned above, if the gunbarrel is not rifled, no rotating band need -be provided on theprojectile. The presence or absence of the rotating band and rifling,however, has no serious influence on my invention.

Propellent powder 47, as is well known, occupies the space insidecartridge case 45 between primer 46 and projectile 26.

However, the illustrative ammunition round has a feature whichinventively associates it with my novel recoilless rifle anddistinguishes it from prior art ammunition rounds. Near its head end 49,the cartridge case is provided with a projecting circular -band uponwhose circumference the thread 51 is formed (see Figs. 1 and 2). Thisthread, as shown in those figures, is engageable with the ammunitionrecesss thread 30 in order to hold the ammunition round in the barrel.

In order to facilitate and to hasten insertion of the ammunition roundinto the barrel and removal therefrom, the spaces 52 (one of which isshown in Fig. l) extending in an axial direction, are formed in theband. These spaces preferably are equally spaced 4from each other, andhave the same expanse angularly relative to the ammunition rounds axis.Naturally, these spaces correspond in shape and number, although theyare slightly larger in size, to the ammunition recesss threaded lugs 31.

in effect, spaces 52 divide the cartridge cases band into a plurality oflugs 53, four in the present instance. These lugs, preferably areequally spaced `from each other, and have the same expanse angularlyrelative to the ammunition rounds axis. As with spaces 52, the lugscorrespond in shape and number, although they are slightly smaller insize, to the spaces (not shown) formed in the ammunition recess. j

The manner of positioning ammunition round 12 into barrel 10, therefore,resolves itself in merely inserting the round, projectile 26 foremost,into ammunition recess 21 as far as the round will go, making certain toalign the barrels lugs 31 with the ammunition rounds spaces 52, thenrotating the round by its head end 49, which remain outside the chambersrear end 16. In so doing, the rounds lugs 53 threadedly engage thebarrels lugs. When no further rotation of the ammunition round ispossible, the round is seated in ammunition recess 21 so that thecartridge cases lateral wall is firmly supported by the charnbers rearportion 16, the barrels openings 19 lie just forward of the cartridgecases neck end 5f), and pre-engraved rotating band27 is in alignmentwith, but not enga-ged to, the barrels rifiing. After the ammunitionround is in barrel 10, electricity-conducting lead wire 48 is connectedto quick connect-disconnect lcontact 41.

in order to remove the cartridge case remaining in the barrel afterfiring the ammunition round, electric lead wire 42 having beendisengaged from contact 41 by the blast of gas issuing from the venturisoutput portion, head end 49 which projects from the rear end of thebarrel is rotated to unlock lugs 53 and 31, and the cartridge case ispulled axially from the barrel.

Although Fig. 2 depicts the ammunition rounds rotating band 27 as beingpre-engraved, it must be understood that this condition is notmandatory. In other words, a plain, unengraved rotating band could beused just as well. As a matter of fact, rotating band 26 could bedispensed with altogether, if desired.

From the foregoing explanation, it is apparent that the cartridge caseshead 49 acts as a breech block Widely used in firearms generally. Since,with my invention, the need for such breech block has been eliminated,the construction of the guns rear end is greatly simplified with aconsequent reduction in weight.

Operation To operate my novel weapon, ammunition round 12 rst isinserted into the barrels ammunition recess 21 in the manner earlierdescribed, and electricity-conducting wire 48 is attached to theterminal blocks contact 41.

After aiming in any convenient manner, the circuit to primer 46 isclosed by operation of a trigger switch (not shown) and the primer isdetonated. Detonation of primer 46 explodes propellent 47. The forceresulting from ignition of the propellent builds up within the cartridgecase to the point where projectile 26 begins to move through the gunsbarrel to the muzzle end. As the projectile moves out of the cartridgecase, some of the gas resulting from ignition of propellent 47 passesbetween the cartridge case and the rear end of projectile 26 andinstantaneously escapes through the barrels openings 19 into theventuris input portion. From there it passes the venturis throat, movesrearwardly through the venturis output portion, then out the rear end ofthe firearm.

Duringgthese actions the recoil neutralizing forces are createdi Inessence, the rear end of projectile 26 acts as' a' valve and canbeshaped along its length toallow av desired opening betweenitself vandthe neck of the cartridge case perlunit'distance of travel of projectilefrom the cartridge case- In'- addition, the combined area of the barrelsopenings can ybe made toany optimum amount. isconveniently possible'toregulate the amount of gases which How through the openings byVappropriately designing the'size, shape and number of openings 19, aswell as thefprojectile-cartridge case relationship.

From the foregoing, it will be apparent that I have simplified thedesign, construction, and operation of recoil-free'guns; that I haveprovided a recoilless'rifle using an imperforate cartridge case; that Ihave provided a recoillessrifle wherein more ecient burning of theammunition: rounds propellent powder yis accomplished; that I haveprovided 'a recoilless'riflein*which the amount and temperature of therearward ow of gases from'the rear endof the gun are reduced; and that Ihave provided' a recoilless rifle in which the projectile, especiallyduring the initial movement from the cartridge case, acts as a valveinfluencingfthe action of the propellent powders gases on the venturi.

My invention is amenable to Various modifications and variations withoutdepartingfrom its originalspirit and scope.- For example, in order Ytohave the outersurface of chamber 13 and the inner surface of recoilneutralizing sleeve `11 define an'annular venturi passagebetween'thernselves, my invention contemplates the combination ofvariously shaped barrels and recoil neutralizing sleeves;

Still other possible ways in which my inventionv can'be modi'ed andvaried pertain to the ammunition round and to the ammunitionround-barrel relationship. In order to have the rear end of projectile26 actasv a valve to control the amount of gas flowing from the open'endof the cartridge case, the projectiles rear end can be vfluted orcontoured in the region enclosed by the'cases neck end 50. Then, uponfiring the ammunition round, the projectile need move only apredetermined amount before gas from the propellent begins to ow fromthe cartridge cases neck end along lthe fluted or contoured portion ofthe projectile and out through the barrels openings 19. If it is desiredto have gas flow from the cartridge case even before theprojectile'begins toV move therefrom, the cartridgel cases'neck endcan'be closedY by some frangiblematerial used in conjunction with theproL jectiles rear end. With this type of arrangement, the frangiblematerial would be fracturedY upon firing the round. Then, before the gaspressure inside the cartridge case would have an opportunity to build upsufficiently to Thus, it

. 3 begin moving thev projectile therefrom, any desired. amountofgaswould bel allowed to passfrorn the car'- tridge-case; throughn the'space previously occupied' by the frangible'material, into theventuri.'4

Still another modication contemplate is to make thev forward end ofammunition recess 21 somewhatlarger than the cartridge cases neck end50; Then, upon firingv the ammunitionY round, the difference in sizebetweenA they are believed to be within the purview of the inventionalready disclosed. Because such variations and modifications arepossible, Ido not wish to be limitedvin'patent coverage bythe limits ofthe foregoing description andV illustrative drawings, but rather only bythe-rnetes and bounds of the'following claim.

I claim: A recoilless vfirearm including a gun tube having a cylindricalforward portion blending into a taperedrear,V

portion and having a plurality of openings forward yof` said rearportion, saidV rear portion being arranged to receive the cartridge caseof an ammunitionround with the forward edge of said case in a planesubstantially" coextensive with the rear edges of said openings and saidforward portion being arranged to receive the roundsA projectile withitsrotating band located between the front andrear edges of said openings,and a recoil neutralizing sleeve encircling said tube to form between itand said tube a venturi having its rear end open to the atmospherel andjoined at its front end to said cylindrical portion at a point forwardof said opening.

References Cited in the iile of this patent UNITED STATES PATENTS625,440 Elliot May 23, 1899 1,434,044, Cooke O.ct.f31, 1922 1,933,694Allen Nov. 7,` 1933 2,436,364 McDowell Feb. 17, 1948 2,478,958 Wheeleret al Aug. 16, 1949 2,529,504 Kroeger et al. Nov..14, 1950 2,537,063Kroeger et al. Ian. 9, 1951 2,693,757 Brandt Nov. 9, 1954 2,701,984Terce Feb. 15, 1955 Y FOREIGN PATENTS 139,773 Germany Apr. 3, 1903`233,347 Great Britain Mar; 11, `192.6

494,910 Belgium Aug, l, 1950 673,431 Great Britain June 4, 1952 Thesemodifications and'

